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IAUC 3763: epsilon Aur; Var STAR IN Ori

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                                                  Circular No. 3763
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM     Telephone 617-864-5758

epsilon AURIGAE
     T. B. Ake, Computer Sciences Corporation: and T. Simon,
University of Hawaii, report the following color-corrected magnitude
measurements of epsilon Aur obtained with the IUE fine-error sensor:
1982 Apr. 4.8 UT, 3.11; Apr. 19.8, 3.14; July 24.5, 3.26; July
29.4, 3.27; Aug. 14.6, 3.25; Aug. 24.4, 3.29; Sept. 23.6, 3.56;
Oct. 18.5, 3.67; Nov. 9.9, 3.79; Nov. 28.3, 3.88; Dec. 23.5, 3.91;
1983 Jan. 2.2, 3.92.  These data indicate that totality occurred
near 1982 Dec. 5.  Preliminary analysis of the ultraviolet photometry
(120-320 nm) at totality suggests that the eclipse is nongrey
with depth of eclipse increasing with decreasing wavelength.
Compared to the fine-error-sensor measurements, the eclipse is ~
0.5 mag deeper at 300 nm and ~ 1.0 mag deeper at 150 nm.  However,
Cepheid-like pulsation in the continuum longward of 140 nm complicates
the determination of the true eclipse lightcurve.  Emission
lines of O I 130.4 nm and Mg II 280.0 nm are present but do not
participate in the variation.

     D. Backman, E. E. Becklin, D. Cruikshank, T. Simon and A.
Tokunaga, University of Hawaii; and R. Joyce, Kitt Peak National
Observatory, report infrared photometry of epsilon Aur during the current
eclipse ingress.  At 1-5 microns the eclipse followed the predicted
visual lightcurve to within 0.05 mag through 1982 Dec. 5, 95-
percent of the way from first to second contact.  On that date the
eclipse was less deep by 0.16 mag at 10 microns (N band) and by 0.32
mag at 20 microns (Q band).  The smaller eclipse depth in N and Q could
be produced by emission from a 600-K blackbody of area 10 AU**2 (the
object's distance from the sun being about 600 pc).

     H. Kosai, Tokyo Astronomical Observatory, telexes that Sugano
has on several recent occasions photographed an object that seems
to be slowly brightening.  Magnitude estimates (Tri-X film) are:
1982 Oct. 30, 16; Dec. 12, 14; Dec. 17, 14; 1983 Jan. 3, 13.
The object appears at B ~ 19 on the Palomar Sky Survey.  It was
perhaps fainter than mag 17 in late 1978.  Observations at the
Kiso station give: 1980 Nov. 18.8 UT, V = 16; 1983 Jan. 11.43, B =
14.2.  Aoki, Maehara and Kosai have measured the position to be R.A.
= 5h35m35s07, Decl. = -4deg18'23".5 (equinox 1950.0).

1983 January 20                (3763)              Brian G. Marsden

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